Rotary kiln and the like



July 9, 1935. J, s'. 4FASTING 2,007,298

ROTARY KILN AND THE LIKE Filed DGO. 9. 1952 INVENTOR i ftions withcascade devices.

Patented July 9, 1935 PATENT OFFICE ROTARY KILN ANDA THE LIKE Johan S.Fasting, Valby, near Copenhagen, Denmark, assignor to F. L. Smidth & Co., New York, N. Y., a, corporation of New Jersey Application December9, 1932, Serial Non 646,515

In Italy December 24, 1931 a' anims. (01.'222-7) The present inventionrelates to rotary kilns, cooling and drying drums in which the materialto be burned, cooled or dried is caused to pass through chambers formedby longitudinal parti- Each chamber or duct receives a portion of thematerial so that the material is distributed over the whole crosssectional area of the drum and is thus exposed to an increasedtransmission of heat, either for heating or cooling or drying,

It has, however, been found that in a drum provided with such devicesthe conveying action of the drum is considerably'reduced. The speed atwhich the material is carried through the drum may, of course, beincreased by making the drum and the cross sectional area of the innerchambers or ducts larger, but as a result the velocity of the airthrough the drum is reduced, with a consequent decreased heattransmission, While the initial costs are increased.

Another mode of increasing the speed at which the material is carriedthrough the drum is to rotate the drum ata higher speed, but thisinvolves a strong stirring up of the material and, consequently, anincrease in the amount of dust y which is mixed with the heatltransmitting air f serve only for the purpose of exposing the materialto the air which traverses the drum, but not for causing the material tomove longitudinally through the drum, is also provided with conveyornights located between the drum wall and the several devices referredto, which devices are not extended fully to the drum wall but leave anannular space between the lifters and the drum wall in which thelongitudinal movement of the material is mainly effected by the conveyorflights. The provision of nights in such space is particularlyeffective, as the relative speeds of the material and of the rotaryparts are higher in that region than at any other region of the interiorof the drum. As it is also desirable that the material be conveyedthrough the drum in a gentle manner, that is, without excessiveagitation, the drum can be rotated at a comparatively low speed While atthe same time the passage of the material through the drum is notundulyv retarded. 'f Material which, for the purpose of being treated inthe drum, has been formed into lumps by ncdulization or briquetting, isconse- 5 quently exposed to breaking up to a lesser extent than when thedrum rotates at high speed.

The invention Will now be described with reference to the accompanyingdrawing, wherein several embodiments are Villustrated and in 10 which:

Figure 1 is a view in cross section of one form of construction;

Figure 2 is a view of the same in longitudinal section; 5

Figure 3 is a view in cross section. of a modified 1 form ofconstruction; and

Figures 4 and 5 are detail views in cross section and on a larger scaleof features of construction to be described.

The partitionsand cascade devices or lifters Within the shell of thedrum may be constructed and arranged in any usual or suitable mannerprovided they are not extended to the drum wall. In the constructionshown in Figures l and 2 the 25 drum I rests on supporting rollers 2,and is provided internally with longitudinal partitions or litters 3which divide the drum tube into a number of longitudinal ducts orchambers but are not extended to the drum wall. Conveyor nights 4' are30 arranged in the annular space between the drum wall I and thepartitions 3 and preferably are placed radially in line with thepartitions and serve to connect them with the shell. In order todistribute the material 5 in the several cham- 35 bers there is providedin connection with each of the nights a, longitudinal, projecting wallor guide vane B which, in the rotation of the drum, serves to direct aportion of the material at the circumference of the drum into theseveral chambers into which the drum has been divided. The amount ofmaterial which passes into the chambers in the interior of the drum isdependent upon the distance between the front edges of these varies 6and the drum wall. The remaining 45 portion of the material at thecircumference of o the drum is subjected, by the nights 4, to a moreheat.VV In order to provide for such adjustment 55 the forward part 61of each guide vane 6 may be movable, as by being hinged, as at 62, andprovided with a supporting rod 63 adjustable from the outside of thedrum, as shown in Figure 4.

For the purpose of adjusting the speed at which the material is carriedthrough the drum the flights 4, or some of them, arel preferablydetachably supported lso that some may be removed or additional flightsadded, or are rotatable relatively to the drum axis, so that they can bemore or less inclined in relation to their direction of movement, as thespeed of the material is to be increased or reduced. As shown in Figure5, at 4l, the flights may be rotatable about a radial axis and beadjustable from the outside by means of a bolt passing through the drumshell. A check of the speed of the material can be obtained, ifdesirable, by turning the flights to such an extent that they counteractthe forward movement of the material and are thus capable of effecting aheaping up of the` material.

In Figure 3 is shown a construction in which the drum consists of twoconcentric tubes I and 1, both the outer tube I and the inner tube 1being provided internally with conveyor flights 4. The flights 4 neednot necessarily be arranged directly opposite the partitions 3 andconnect the partitions to the drum wall, but may be placed freely in thespaces between the partitions.

Various changes in details of construction and arrangement can be madeto suit the convenience of the manufacturer or user without departingfrom the spirit of the invention, except so far as it is defined in theaccompanying claims.

I claim as my invention:

1. In a rotary kiln and the like, the combination of a drum providedwith longitudinal chamberforming partitions which do not extend to thedrum Wall but leave a space for the passage of material'adjacent 'to the'drum wall, conveyor flights between the drum wall and such partitions,and longitudinal, projecting walls or guide vanes to direct a portion ofthe material at the circumference of the drum into the chambers of thedrum, the forward parts of the longitudinal, projectingV walls or guidevanes being adjustable so that they can be moved towards or away fromthe drum wall.

2. In a rotary kiln and the like, the combination of a drum providedwith longitudinal chamber-forming partitions which do not extend to thedrum wall but leave space for the passage of material adjacent to thedrum wall, conveyor flights between the drum wall and such partitions,and longitudinal, projecting Walls or guide vanes to direct a portion ofthe material at the circumference of the drum into the chambers of thedrum, the forward parts of the guide varies being hinged to the mainparts and provided with adjustable supports.

JOHAN S. FAS'I'ING.

